Synthesize, Don't Summarize
The chief difference between these two tactics is that the former deals with themes while the latter deals with facts/experiences, though there is some overlap. You do not need to recap the essay paragraph-by-paragraph. You do not need to remind the reader of the experiences you have discussed (except as individual experiences might be tied to certain themes you want to synthesize).
You do want to reiterate key themes, but preferably not in a way that merely repeats them. Instead, in synthesizing these key themes in your conclusion, you should ideally be adding a fresh perspective. Try to tie themes together and demonstrate how they complement each other. In doing so, you should always avoid trite and clichéd generalizations.
In this essay, this applicant uses the conclusion to synthesize the second half of the essay. It's worth noting that he does not mention the content about recovering from addiction, because he could have tied this in with his renewed interest in public policy. Nevertheless, the concluding sentences do an effective job of linking his past experiences with his career goals: "After getting my master's in public administration, I would like to work in the area of economic development in the Third World, particularly Latin America. The setting might be a private (possibly church-based) development agency, the UN, the OAS, one of the multilateral development banks, or a government agency. What I need from graduate school is the academic foundation for such a career. What I offer in return is a perspective that comes from significant involvement in policy issues at the grassroots level, where they originate and ultimately must be resolved."
Seeing how the pieces fit together leaves us with a clear point to take away. Moreover, the last sentence is key to the lasting impression he creates, as it provides a fresh interpretation of the significance of his work at the grassroots level.
If in the process of synthesizing you are able to invoke your introduction, you will add to your essay a further sense of cohesion and closure. There are a number of different ways this can be accomplished. For example, you might complete a story you started in the introduction, as in this essay, or you might show how something has changed in your present since the timeframe of the introduction.
Expand on Broader Significance-Within Reason
One way to ensure that your closing paragraph is effective is to tie your ideas to some broader implications, whether about yourself or your field. However, do not get carried away. Some applicants feel they must make reference to changing the world or derive some grand philosophical truths from their experiences. Remember to stay grounded and focused on your personal details.
This applicant's conclusion ties his goals in teaching to a broader issue about research limitations at smaller liberal arts colleges. He does not express the goal of revolutionizing education, but instead simply wants to make a contribution that has personal significance to him. The final sentence invokes the tradition of scholars before him. Such a tactic is not usually advisable, because it can sound forced and generic, but in this case, the applicant has established his focus on a specific intellectual topic-human memory-so it's not as vaguely trite as invoking Plato, Descartes, and Kant in the search for truth.
Don't Add Entirely New Information-Except to Look Ahead
We have used the word "fresh" here several times, and what we're mainly talking about is perspectives and ideas. You should avoid adding entirely new information about your experiences. In shorter essays, you may have to pack details everywhere, but in general, if it's an important experience, it should come earlier.
That said, writing about your future goals is a strong way to end. After you have established your background and qualifications in the previous paragraphs, delineating your goals can help synthesize these topics, because you are tying your themes together in the context of where you will go next.
This applicant's conclusion is a straightforward, well thought out description of her professional goals. Such an ending demonstrates to the reader that she has given much consideration to her future and the role a Ph.D. in literature can play in it. Moreover, she makes clear that while she has definite career goals in mind, she also appreciates literature for its own sake. This kind of natural affinity for her subject of study serves to make her a dedicated and genuinely engaged student, and, therefore, a more attractive candidate to the admissions committee.
